The present invention relates to a hydraulic ram suited to actuate tools or the like where it is desirable to detect and adjust the stroke of a piston within a cylinder.
German published patent application DE-A-37 05 190 discloses a cylinder-piston-assembly wherein the piston is displaced by a pressurized fluid. A stop member is screwed to a piston rod which extends through one end of the cylinder. The stop member is provided with a number of circumferential grooves so that its position relative to the piston rod may coarsely be read.
In other known systems, the piston stroke is sensed by electronic means which, however, is costly and nevertheless insufficiently accurate.